A ventilatory strategy of minimal ventilator support (permissive hypercapnia) before 12 hours and continued for 10 days or until extubation and/or a stress dose of corticosteroid (CS) started before 24 hours and tapered over 10 days will be evaluated to determine whether the incidence of death before discharge or chronic lung disease in extremely low birthweight infants can be reduced. (This is a NICHD Neonatal Research Network Trial.)